There are plenty of cheaper -- ok properties -- available for $28-$50 along the road next to the Radisson or even in the city center itself. When you get past immigration and then customs at DEL there is an area in the arrivals area -- before where the hotel drivers are standing with placards with names -- that has some "tourist"-oriented kiosks. They can make reservations on arrival based on your budget and many of those include one-way transportation to the budget hotel or you can arrange for the prepaid car at the same time as the hotel booking.

Alternatively, if you have a booking already made before arrival and have the address for the hotel in hand, you can take a prepaid taxi to the hotel of your choosing by booking the prepaid cars either in that non-busy part of the arrival area where the "tourist"-oriented kiosks are. However, the prepaid taxis outside the arrival waiting hall -- take the exit on the right side when walking from customs to the outside -- are much cheaper but can be a bit overwhelming as there is an even bigger mass of people waiting outside there.

As this sounds like your first trip to DEL -- and given the budget -- I would generally recommend getting your hotel booking done in advance and taking a prepaid taxi. Just remember to have the hotel's address and phone number in hand -- including asking for the neighborhood name and the major street/intersection/marketplace/store which is closest to it. (Finding a hotel driver -- especially from the non-higher end properties -- can be a major pain or even downright unreliable.)

Would your train to Ludhiana be leaving from the Nizamuddin train station or the DEL Central Rail Station? I'm presuming it's leaving from the one closer to Connaught Place since that is from where most foreign visitors generally start their trips. I certainly recommend getting a hotel closer to the train station than to the airport since morning traffic into central DEL can be rather slow.

As my experience with the budget ranges in DEL is slim, I'll have to ask around. I don't know well Pahar Ganj but that is the area backpackers and most budget tourists usually head to in DEL.

My experience with the budget ranges in DEL is slim since most of my friends/associates on a tight budget usually get put up at the India International Center, Habitat Center, the _____ State guest houses -- each Indian state has one in DEL -- or a few private guest houses.